A current switching circuit incorporated in a semiconductor device switches an output of the device between high and low states. The current switching circuit typically controls the switching of two transistors in a well known push-pull configuration.
Current switching noise (current spikes) occurring when the transistors are switched causes a problem within the device, especially if more than one output is being switched simultaneously, as in the case of a parallel multi-line data path where several lines may be switched simultaneously.
Current switching circuits are known which slow down the transistor slew rate (voltage-time gradient), hence reducing the magnitude of the current spikes. However, these also effectively reduce the switching speed of the output. Therefore designers utilising known switching circuits have been forced to choose between switching circuits which are either slow or noisy.
This invention seeks to provide a current switching circuit in which the above mentioned disadvantages are mitigated.